1. Field of the Invention
The present invention relates to a protein foam fire-extinguishing chemical used in fire-extinguishing facilities, as well as an aqueous foam solution. In particular, the present invention relates to a protein foam fire-extinguishing chemical having foaming properties usable as a foam fire-extinguishing chemical diluted even at a low concentration of 2% by volume or less, as well as an aqueous foam solution.
2. Description of the Prior Art
A conventional protein foam fire-extinguishing chemical is in a liquid form comprising a product obtained by hydrolyzing protein (referred to hereinafter as xe2x80x9cprotein hydrolyzatesxe2x80x9d) as a base material and a foam stabilizer such as iron salts, a pour point depressant such as ethylene glycol, etc. compounded therein. As an aqueous foam solution released to a site of fires, there are 6% aqueous foam solution and 3% aqueous foam solution. The 6% aqueous foam solution is an aqueous foam solution consisting of 6 vol-% protein foam fire-extinguishing chemical mixed with 94 vol-% water or seawater, while the 3% aqueous foam solution is an aqueous foam solution consisting of 3 vol-% protein foam fire-extinguishing chemical mixed with 97 vol-% water or seawater. At present, the 3% aqueous foam solution is mainly used.
Whether the foaming properties of a protein foam fire-extinguishing chemical are good or not is determined depending on whether the bubbling properties and foam stability thereof are good or not. As the concentration of a protein foam fire-extinguishing chemical having bubbling properties is increased, the bubbling properties reaches the maximum (plateau) at a certain concentration, and as the concentration is further increased, the bubbling properties are lowered.
The foam stability of an aqueous solution of protein hydrolyzates containing a foam stabilizer is high, but the bubbling properties thereof are moderate. Accordingly, the bubbling properties have been improved heretofore by increasing the concentration of the aqueous solution of protein hydrolyzates thereby achieving foaming properties (foam stability and bubbling properties) making it as a foam fire-extinguishing chemical. That is, unless the concentration of the diluted aqueous foam solution is 3% by volume or more, foaming properties making it usable as a foam fire-extinguishing chemical have never been achieved heretofore.
However, if the 3% aqueous foam solution is to be used at the present when an object (e.g. petroleum tank) of fire extinction becomes enormous and large-scaled, a large amount of the protein foam fire-extinguishing chemical is necessary for the relationship of the mixing ratio described above. Accordingly, a tank for storing the protein foam fire-extinguishing chemical is large-scaled, and a container for stockpiling thereof is also enlarged. Further, the protein foam fire-extinguishing chemical should be conveyed repeatedly from a base for stockpiling thereof to a site of fires in order to achieve a necessary amount of the protein foam fire-extinguishing chemical.
These problems can be solved by reducing the amount of the protein foam fire-extinguishing chemical while maintaining practical foaming properties thereof. Accordingly, the present inventors attempted to reduce the amount of water incorporated into the conventional protein foam fire-extinguishing chemical in order to reduce the concentration thereof diluted with water or seawater at the time of use. However, the present inventors found that this is not practical because the viscosity of the protein foam fire-extinguishing chemical is significantly increased upon reduction of the amount of water in the protein foam fire-extinguishing chemical, thus making it difficult or even infeasible to proportionally mix the resulting aqueous foam solution uniformly and stably in an existing conventional system of mixing a foam fire-extinguishing chemical (that is, a compression or compression-feeding pressure proportional system, a pump proportional system, a line proportional system etc.), resulting in failure to form a normal aqueous foam solution.
The object of the present invention is to provide a protein foam fire-extinguishing chemical and an aqueous foam solution, which can be proportionally mixed without significantly increasing the viscosity of the protein foam fire-extinguishing chemical in a usual system of mixing a foam fire-extinguishing chemical and has foaming properties making itself usable as a foam fire-extinguishing chemical even diluted at a concentration of 2% by volume or less, thus reducing the size of a storing tank and container therefor as well as reducing the number of times the chemical is conveyed from a base for stockpiling to a site of fires.
The protein foam fire-extinguishing chemical of the present invention is a protein foam fire-extinguishing chemical in a liquid form comprising protein hydrolyzates as a base material as well as a foam stabilizer and a foaming assistant compounded therein, wherein the amount of the foaming assistant compounded is 8 to 20% by weight.
In this case, one or more members selected from the group consisting of 2-methyl-2,4-pentanediol, 3-methyl-3-methoxy butanol, diethylene glycol monobutyl ether and diethylene glycol monoisopropyl ether are contained as the foaming assistant. Further, it is preferable that the protein hydrolyzates are compounded in an amount of 25 to 40% by weight in terms of the solid content thereof.
The aqueous foam solution of the present invention is characterized in that the concentration of the protein foam fire-extinguishing chemical having the composition described above is made 2% by volume or less by mixing it with water or seawater.
The aqueous solution of protein hydrolyzates containing a foam stabilizer has high foam stability and moderate bubbling properties, and the bubbling properties can also be improved by incorporation of a foaming assistant. As the foaming assistant, one or more members selected from the group consisting of 2-methyl-2,4-pentanediol, 3-methyl-3-methoxy butanol, diethylene glycol monobutyl ether and diethylene glycol monoisopropyl ether are contained.
As a result of incorporation of such a foaming assistant, the protein foam fire-extinguishing chemical can be proportionally mixed uniformly and stably while maintaining excellent foaming properties (foam stability and bubbling properties) without significantly increasing the viscosity thereof in a usual system of mixing a foam fire-extinguishing chemical, and can further demonstrate foaming properties usable as a foam fire-extinguishing chemical in an aqueous foam solution diluted even at a low concentration of 2% by volume or less.
The amount of the foaming assistant compounded is preferably 8 to 20% by weight, more preferably 10 to 15% by weight. Depending on the type of the foaming assistant compounded, the amount of the foaming assistant can be increased or decreased within this range. When the amount of the foaming assistant is higher than said range, the viscosity of the protein foam fire-extinguishing chemical is significantly increased to make uniform, stable and proportional mixing infeasible in a usual system of mixing a foam fire-extinguishing chemical, thus making practical use infeasible, while the amount of the foaming assistant is lower than said range, the protein foam fire-extinguishing chemical upon dilution at a low concentration of 2% by volume or less comes to have a lower degree of foaming with a 25% reduction time of 1 minute or less, thus failing to provide an normal aqueous foam solution usable for extinguishing fires.
The amount of the protein hydrolyzates compounded is preferably 25 to 40% by weight, more preferably 30 to 35% by weight, in terms of the solid content thereof. When the amount of the protein hydrolyzates compounded is larger than 40% by weight, the viscosity of the protein foam fire-extinguishing chemical is significantly increased to make uniform, stable and proportional mixing infeasible in a usual system of mixing a foam fire-extinguishing chemical, thus making practical use infeasible, while the amount of the protein hydrolyzates is smaller than 25% by weight, the protein foam fire-extinguishing chemical upon dilution at a low concentration of 2% by volume or less comes to have a lower degree of foaming with a 25% reduction time of 1 minute or less, thus failing to provide an normal aqueous foam solution usable for extinguishing fires.
According to the present invention, the protein foam fire-extinguishing chemical can, upon being mixed with water in a usual system of mixing a foam fire-extinguishing chemical, be used practically without significantly increasing the viscosity thereof, and can thus provide an aqueous foam solution diluted at a low concentration of 2% by volume or less.
The aqueous foam solution diluted even at a low concentration of 2% by volume or less can demonstrate foaming properties usable as a foam fire-extinguishing chemical and is not inferior to the conventional 3 vol-% aqueous foam solution. Further, the aqueous foam solution in the present invention solves disadvantages of the conventional 3 vol-% aqueous foam solution, such as requirements for a large-scale tank and container for storing the protein foam fire-extinguishing chemical and a large number of times the chemical is conveyed from a base for stockpiling to a site of fires, thus achieving the effects of reducing the size of the storing tank and container as well as reducing the number of times the chemical is conveyed to the site of fires.
Preferable embodiments of the present invention are listed below.
(a) A protein foam fire-extinguishing chemical, which comprises 32% by weight of protein hydrolyzates as solids compounded with 1% by weight of iron sulfate, 15% by weight of 3-methyl-3-methoxy butanol and 52% by weight of water.
(b) A protein foam fire-extinguishing chemical, which comprises 32% by weight of protein hydrolyzates as solids compounded with 1% by weight of iron sulfate, 15% by weight of 2-methyl-2,4-pentanediol and 52% by weight of water.
(c) A protein foam fire-extinguishing chemical, which comprises 32% by weight of protein hydrolyzates as solids compounded with 1% by weight of iron sulfate, 5% by weight of 2-methyl-2,4-pentanediol, 10% by weight of diethylene glycol monobutyl ether and 52% by weight of water.
(d) A protein foam fire-extinguishing chemical, which comprises 32% by weight of protein hydrolyzates as solids compounded with 1% by weight of iron sulfate, 15% by weight of diethylene glycol monoisopropyl ether and 52% by weight of water.
(e) A protein foam fire-extinguishing chemical, which comprises 36% by weight of protein hydrolyzates as solids compounded with 1% by weight of iron sulfate, 5% by weight of 2-methyl-2,4-pentanediol, 10% by weight of diethylene glycol monobutyl ether and 48% by weight of water.
(f) A protein foam fire-extinguishing chemical, which comprises 32% by weight of protein hydrolyzates as solids compounded with 1% by weight of iron sulfate, 8% by weight of 2-methyl-2,4-pentanediol (foaming assistant), 5% by weight of ethylene glycol (pour point depressant), and 54% by weight of water.
(g) A protein foam fire-extinguishing chemical, which comprises 32% by weight of protein hydrolyzates as solids compounded with 1% by weight of iron sulfate, 10% by weight of 2-methyl-2,4-pentanediol, 5% by weight of ethylene glycol and 52% by weight of water.
(h) A protein foam fire-extinguishing chemical, which comprises 32% by weight of protein hydrolyzates as solids compounded with 1% by weight of iron sulfate, 15% by weight of 2-methyl-2,4-pentanediol, 5% by weight of ethylene glycol and 47% by weight of water.
(i) A protein foam fire-extinguishing chemical, which comprises 32% by weight of protein hydrolyzates as solids compounded with 1% by weight of iron sulfate, 20% by weight of 2-methyl-2,4-pentanediol, 5% by weight of ethylene glycol and 42% by weight of water.
(j) An aqueous foam solution, wherein the concentration of the protein foam fire-extinguishing chemical described above is made 2% by volume or less by mixing it with water or seawater.